1. Field of the Invention
The present invention relates to a plasma ion mass spectrometer and a plasma mass spectrometry using the same.
2. Description of the Related Art
A plasma ion mass spectrometer has a function to ionize a sample in plasma at a high temperature, and to perform mass spectrometry for the ionized sample. Such a plasma ion mass spectrometer has been disclosed, for example in Japanese Patent Laid-open No. Sho 60-133648.
A plasma ion mass spectrometer is suitable for analysis of trace amounts of elements contained in a sample, particularly, for analysis of trace amounts of poisonous elements (such as chromium, lead and mercury) contained in water of rivers and marshes, or lakes and marshes. It is also effective for analysis of trace amounts of impurities (such as boron, phosphorous and aluminum) contained in ultra-pure water used for cleaning a wafer in a process of fabricating a semiconductor electronic device such as a memory chip for a computer.
The above-described plasma ion mass spectrometer, however, is disadvantageous in that ultraviolet radiation having a high intensity is generated by plasma and it gives background noise to an ion detector, deteriorating detection accuracy.